1. Field of the Invention
The present invention relates to a photosensitive belt cartridge for keeping a photosensitive belt to be installed in an electrophotographic image forming apparatus, and a photosensitive belt installation device and method employing the same. Korean Patent Application No. 00-39092, filed Jul. 8, 2000, is incorporated herein in its entirety by reference.
2. Description of the Related Art
As shown in FIG. 1, an electrophotographic image forming apparatus such as a color laser printer includes a photosensitive belt 10 circulating around a continuous loop while supported by a plurality of rollers 11, 12, and 13 installed in a main body of the image forming apparatus. On one surface of the photosensitive belt 10, an image to be printed is developed by a developing unit 15, and the developed image is dried while passing by a drying unit 16, and then is printed on a paper sheet at a transfer unit 14 including a transfer roller 14a and a fuser roller 14b. Here, the unit around which the photosensitive belt 10 circulates is called a belt unit.
However, as such a photosensitive belt 10 is used for a long time, a developed image gradually deteriorates in its precision. Therefore, when the photosensitive belt 10 reaches the end of its usable life, the photosensitive belt 10 must be replaced with a new one to continue to develop a neat image. However, in order to replace the photosensitive belt 10 in a conventional method, the photosensitive belt 10 is replaced by fitting it directly by hand in its installation position within the main body of the apparatus. In this method, one 13 of the plurality of rollers 11, 12, and 13 is installed to be movable as shown in dotted lines in FIG. 1, and when replaced, the photosensitive belt 10 is loosened by moving the roller 13 to the position shown in dotted lines, and then is removed from its installation position by hand. Subsequently, after a new photosensitive belt is inserted into its installation position by hand, the new photosensitive belt is tensioned by moving the roller 13 to its original position.
However, since the shape of the endless photosensitive belt 10 is not a rigid patterned shape, and the endless photosensitive belt 10 is as flexible as paper, there are problems in that to replace the photosensitive belt 10 by fitting it in place by hand is bothersome and difficult in itself, and, in addition, the photosensitive belt 10 may be erroneously installed depending upon a worker who performs the replacing job.
Therefore, to solve those problems, a cartridge 20 for receiving such a photosensitive belt 10 as shown in FIG. 2 has been proposed. The main body of the photosensitive belt cartridge 20 is comprised of a hard case having a shape similar to the endless track of the belt unit, and leaf springs 21 installed at the inner circumferential surface of the cartridge 20 and supporting the photosensitive belt 10 in a continuous loop state (i.e., in a state as the photosensitive belt 10 is installed around the belt unit). Reference symbol S denotes spare space provided so that the roller 13 can be moved to tension the photosensitive belt 10 when the photosensitive belt 10 is installed around the belt unit. Therefore, when the photosensitive belt 10 is installed, the cartridge 20 receiving the photosensitive belt 10 is pushed on, in the direction of arrow xe2x80x9cA,xe2x80x9d around the belt unit within the image forming apparatus. When the roller 13 is moved as much as the spare space (S) as shown in FIG. 3, the photosensitive belt 10, supported by the leaf springs 21, is tightly tensioned. At this time, when the cartridge 20 is pulled back toward the outside, only the photosensitive belt 10 remains around the belt unit.
When the above hard-case cartridge 20 is used, the photosensitive belt 10 can be conveniently installed as described above. However, it is a problem to store the cartridge 20. That is, since the cartridge 20 has nearly the same shape as that of the belt unit around which the photosensitive belt 10 circulates in an endless belt state, the volume of the cartridge is larger than the belt unit, and there is no way to reduce the volume any more due to the hard case of the cartridge 20. Therefore, although the photosensitive belt 10 can be safely stored, and be easily installed, it is troublesome to store the cartridge 20.
To solve the above problem, it is an objective of the present invention to provide a photosensitive belt cartridge adapted to occupy small space during storage, and to be used in replacing a photosensitive belt in a convenient and fast manner, and a photosensitive belt installation device and method employing the same.
Accordingly, to achieve the above objective, there is provided a photosensitive belt cartridge of an electrophotographic image forming apparatus including: a soft cartridge which has the endless track shape of a belt unit of the image forming apparatus, which receives a photosensitive belt therein in the endless track shape, which can be rolled up with the photosensitive belt received therein, and which has flexibility so that the rolled-up soft cartridge can be restored back to its original shape when an external force is removed; and a hard cartridge in which the soft cartridge is stored in a rolled-up state.
In addition, there is provided a photosensitive belt installation device of an electrophotographic image forming apparatus for assisting in the installation of a photosensitive belt around a belt unit within the image forming apparatus comprising: an installation guide member which is attached to a front frame of the belt unit when the photosensitive belt is installed, and which has a sloping surface gradually enlarging in a direction from the outside of the image forming apparatus to the belt unit; and a soft cartridge in which the photosensitive belt to be installed around the belt unit is supported by predetermined restricting means in the endless track shape. The soft cartridge is a flexible cartridge having a shape of the endless track of the belt unit, and is open on both sides. The soft cartridge is shaped so that one open side of the soft cartridge fits over the sloping surface of the installation guide member. The soft cartridge is completely pushed around the belt unit along the sloping surface, and, then, the soft cartridge is pulled out and the photosensitive belt is freed from the restricted state by the restricting means, with the photosensitive belt formerly received in the soft cartridge remaining around the belt unit.
In addition, there is provided a photosensitive belt installation method of an electrophotographic image forming apparatus for installing a photosensitive belt around a belt unit within the image forming apparatus including the steps of: preparing a soft cartridge which is a flexible cartridge having a shape of the endless track of the belt unit, which is open on both sides, and in which the photosensitive belt to be installed around the belt unit is supported by predetermined restricting means in the endless track shape; installing an installation guide member which has a sloping surface gradually enlarging in a direction from the outside of the image forming apparatus to the belt unit at the front frame of the belt unit; fitting one open side of the soft cartridge to the sloping surface of the installation guide member, and completely pushing the soft cartridge around the belt unit along the sloping surface; and causing the photosensitive belt received in the soft cartridge to remain around the belt unit by pulling out the soft cartridge from the image forming apparatus after the photosensitive belt is freed from the restricted state by the restricting means.